Heretofore, the backstop comprising a cylindrical one-way clutch was entered and fixed at one end in an opening in the reducer casing with an extension of the reducer input shaft extending axially through the center of the clutch and engaging a plurality of circularly arranged locking elements therein. In this prior arrangement, wherein the one-way clutch is provided with a plurality of circularly arranged locking elements, was the problem of achieving and maintaining the degree of concentricity required between the circularly arranged locking elements and the extension of the reducer shaft, which engaged the locking elements, to result in each of the circularly arranged locking elements being stressed by a reversal force so as to jointly preclude a reversal of the reducer. Establishing and maintaining this degree of concentricity was both difficult and costly and in the prior arrangement frequently just one or a part of the plurality of the circularly arranged locking elements absorbed all of the reversal force resulting in a malfunctioning backstop.